An inspector applies 2024 IRC G2427.2.1 to a U.S. installation of a Rheem RTGH indoor direct-vent water heater using the two-pipe vertical arrangement in manual AP21820 Rev. 04. The supplied detail places the intake termination opening 12 inches above the roof and requires the exhaust termination opening at least 12 inches above that intake opening. Snow and other terminal-clearance conditions require no greater height, and all other installation requirements are met. What is the minimum exhaust-opening height above the roof for this arrangement?
- 2 feet
- B3 feet
- C4 feet
- D5 feet
Where to look it up
https://files.rheem.com/blobazrheem/wp-content/uploads/sites/2/RTGH-Use-and-Care-Manual.pdf
Why A is correct
The exhaust opening must be at least 12 + 12 = 24 inches, or 2 feet, above the roof in this specified two-pipe arrangement. The first 12 inches is the stated intake height; the second is the manufacturer’s exhaust-to-intake separation. G2427.2.1 requires following the listed direct-vent appliance’s instructions; it does not establish a universal 4-foot roof height. Sources: Rheem AP21820 Rev. 04, page 34; 2024 IRC G2427.2.1. https://files.rheem.com/blobazrheem/wp-content/uploads/sites/2/RTGH-Use-and-Care-Manual.pdf ; https://dos.ny.gov/nys-residential-code-noa-7242025